A prior art design for an abdominal aortic tourniquet can be seen in published pending application Ser. No. 12/150,728 listed John Croushorn as inventor (“the '728 application”), the '728 application is incorporated by reference in its entirety particularly for its discussion on using an abdominal aortic tourniquet for occluding blood flow. The prior art design is intended to occlude the descending aorta at the bifurcation into the left and right iliac arteries. The prior art design is a non-invasive device intended for cross-clamp of the descending aorta. The primary use for the prior art design is for pelvic and lower extremity penetrating trauma is typically not treatable out in the field with a conventional tourniquet application. In use of the prior art design, the device is buckled around the patient, the bladder is positioned over the umbilicus, the provided belt is tightened by pulling a strap and then a windlass and the bladder is inflated to the appropriate pressure.
In detail the prior art has provided a portable pneumatic aortic occlusion device that is comprised of the following components:
(1) A torso securing strap made of webbing (with or without hook & loop fasteners attached to the webbing). The webbing is attached to the Compression Latch and goes around the torso just above the iliac crest;
(2) A base plate made of injected molded plastic which is used to connect the pressure application mechanism to the torso securing strap and to provide a stable platform for anchoring the directed bladder. The base plate contains an offset orifice which allows the pressure tubing to connect from the inflation mechanism to the bladder. A retention clip may be used to retain the tubing if a hand drive pressure pump is utilized. A separate retention clip may be incorporated to retain a CO2 cartridge on a CO2 cartridge variation. The underside of the base plate is lined with a foam padding that extends beyond the edges of the base plate;
(3) A directed bladder on the underside of the base plate is a self-contained pneumatic bladder. A valve stem is incorporated in the bladder.
(4) A threaded CO2 Cartridge for the CO2 variation or a hand driven pressure pump;
(5) A bladder sleeve to cover the bladder to protect it from exterior puncture or environmental exposure. The bladder sleeve may be physically attached to the bladder allowing it to be fully compressed when the bladder is empty of air;
(6) An optional pressure release valve to aid in securing the bladder pressure once inflated;
(7) A right angle elbow connector to connect the CO2 cartridge to the Presta Valve stem; and
(8) A three-part compression having a two hinged latch to provide final compression on the abdomen with the compression webbing.
When constructing the prior art design the latch is prepared separately or purchased already assembled prior to assembly of the device. The torso securing strap is prepared by cutting a 120 cm piece of 4 cm nylon webbing. Hook and loop fasteners may or may not be attached to one side of the webbing. The torso securing strap is attached at one end to the compression latch (the terminal arm of the latch) by 4 rivets. The latch base is fixed to the base plate with one piece of looped webbing anchored between the latch and the base plate by 4 rivets. This loop of material is what the buckle is fixed to. The base plate foam pad is placed o the underside of the base plate (side toward patient). The bladder is positioned under the base plate. The valve stem is passed up through the orifice prepared in the base plate and secured by a small washer and the stem nut. A bladder sleeve is positioned over the top of the bladder and attached to the underside of the base plate. With the CO2 variation, the elbow connector and threaded CO2 cartridge are packaged with the pneumatic aortic compression system With manual inflator variation using a hand pump, the bulb pump to include the pressure valve and one way valve at the base of the pump is bought commercially or prepared separately. The tubing is permanently fixed to the bladder. A pressure gauge for warning if the pressure is dropping in the bladder or maximum pressure has been reached can be provided.
To use the prior art design the torso securing strap is fed around the patient's body with the strap lying above the iliac crests. It is fed through both slots in the buckle. The base plate is positioned just left of midline. The slack should be removed from the strap. The latch is closed. The Presta valve is opened and the elbow connector applied to the Presta valve stem. The CO2 threaded cartridge is attached to the elbow connector. The cartridge is screwed to its maximum depth to penetrate the cartridge. The cartridge is gently unscrewed to release air into the bladder. The flow of CO2 can be stopped by screwing the cartridge into the elbow connector. A pressure indicator may be incorporated on the device to warn if high pressure exists in the bladder or that the pressure is falling. Generally the bladder is inflated until he desired effect of cessation of bleeding occurs, or the desired effect of preload return to the heart is achieved. If a manual bulb hand-pump can be utilized in place of the CO2 cartridge.
This prior art design requires a separate gas holding inner bladder and outer shell cover, and despite its objectives is also known to not provide for sufficient point pressure required to occlude an artery. The present invention provides for an improved abdominal aortic tourniquet which overcomes the problems of the prior art two-piece design and insufficient amount of point pressure.